Highly stable and sensitive NO₂ sensor based on Bi₂S₃ with synergistic effect of multi-scale structure and Pt nanoparticles sensitization over a wide humidity range

NO₂ is a prevalent atmospheric pollutant known to cause significant harm to both the environment and human health. In practical applications, the development of NO₂ sensors capable of functioning over a wide humidity range with high sensitivity and stability is crucial. Here, the Pt-decoration multi-scale three-dimensional Bi₂S₃ nanoflower structure assembled by one-dimensional nanorods and two-dimensional reticulated nanomeshes was constructed by integrating the geometrical and electronic effects. The Pt/Bi₂S₃ based sensors exhibit a high response of 3.92 and rapid response/recovery times of 15 s/136 s to 1 ppm NO₂ at room temperature. Furthermore, the Pt/Bi₂S₃ based sensors show excellent selectivity and stability across a wide range of humidity levels (10 %-90 %RH). Finally, a portable NO₂ detector was designed for data acquisition and wireless transmission to enable real-time gas detection and hazard warning. Our study presents a multi-scale structure for sensitive materials design and practical application of high-performance NO₂ sensors operated in a wide humidity range at room temperature.